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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Importing same class that is in 2 different files does not identify it as same class","articleBody":"Lets say I have a class called `AbstractClass`:\n\n```\n// animal.ts\nexport abstract class Animal {\n   public abstract talk(): String;\n}\n\n// cat.ts\nimport {Animal} from \"./animal\";\n\nexport class Cat extends Animal {\n    public talk(): String {\n        return \"meow\";\n   }\n}\n\n// dog.ts\nimport {Animal} from \"./animal\";\n\nexport class Dog extends Animal {\n   public talk(): String {\n       return \"whoof whoof\";\n   }\n}\n```\n\nNow I have another module that has dependency on that class.\n\n```\nimport {Animal} from \"animal-module/animal\";\n\n// play-with-animal.ts\nexport class PlayWithAnimal {\n    private animal: Animal;\n\n    constructor(animal: Animal) {\n        this.animal = animal;\n    }\n\n   public makeAnimalTalk(): void {\n        console.log(this.animal.talk());\n   }\n}\n```\n\n```\n// animal.component.ts\nimport {PlayWithAnimal} from \"play-with-animal-module/play-with-animal.ts\"\nimport {Cat} from \"animal-module/cat\";\n\nsomeFunction() {\n    let cat: Cat = new Cat();\n    let playWithAnimal: PlayWithAnimal = new PlayWithAnimal(cat);\n\n   // here I get error saying:\n  // TS2345: Argument of type 'Cat' is not assignable to parameter of type 'Animal'. 'Animal' is not a class derived from 'Animal'. \n}\n\n```\n\nHere is how the folder structure is. I am using `node` to resolve the modules.\n\n```\n- app\n   animal.component.ts\n   // app has dependency of animal-module\n- node_modules\n   - animal-module\n        animal.ts\n        cat.ts\n        dog.ts\n   - play-with-animal-module\n      play-with-animal.ts\n      // talking-animal-module has dependency of animal-module\n      - node_modules\n         - animal-module\n            animal.ts\n            cat.ts\n            dog.ts\n\n```\n\nMy finding so far is that, as in the `dog.ts` or `cat.ts`, I have imported the `Animal` as `import {Animal} from \"./animal\";`. Notice the relative path.\n\nHowever in `PlayWithAnimal` or `AppComponent` the module is resolved using the node resolution. Somehow typescript thinks that they are separate classes (eventhough) they are same as they are being loaded from different file paths.\n\nIf I wrap Animal in a `exports module 'SomeModule'` and update the code to use `SomeModule.Animal` then it works fine even if I load the class from 2 different files. However if I do so then I lose ability to import multiple classes like import `{Animal, SomeotherClass}`.\n\nSo my question is:\n1. Is this by design or its an issue?\n2. If this is by design then how are we meant to resolve the modular dependencies?\n\nThanks.\n","author":{"url":"https://github.com/adikari","@type":"Person","name":"adikari"},"datePublished":"2016-04-13T00:48:38Z","url":"https://github.com/microsoft/TypeScript/issues/8052"}